You have to hit every target with a ball. Find one of the black balls scattered around the playground (they look like kettlebells) and throw it at each of the four archery targets.

As soon as you gain control of Lara, the three first targets are to your right. Target 1 is hanging on the trunk of a tree.
As soon as you gain control of Lara, the three first targets are to your right. Target 2 is hanging from a branch on a tree.
As soon as you gain control of Lara, the three first targets are to your right. Target 3 is standing on a tripod.

This one is in a slightly different location than the other two. In the back of the garden (behind Lara when you first gain control of her) there is a hammock. Target 4 is hanging from a tree branch above the hammock.